Sugar cane belongs to the Poaceae family and can grow to heights of 2.5 to 4.5 meters. It contains 11% to 17% saccharose by weight and 11% to 15% fiber (lignocellulosic material) by weight. The cane is cut, along with the stalk, and is transported by truck to the plant.
The cane is unloaded onto a feed table and either washed with water or dry-cleaned in order to remove earth, debris, and straw. This stage is known as the receipt of the cane.
Preparation and Milling of the Cane
After receipt, the cane goes to the preparation stage, which takes place inside a piece of equipment (the chopper) that consists of knives rotating at high speed (500 to 1200 rpm). The cane is cut into small, short pieces (“cuttings”), which form a compact uniform layer that is then sent to the defibrator. The purpose of this piece of equipment is to encourage a high degree of disintegration of the cane, so as to facilitate the extraction of the sugars during the milling stage. The defibrator consists essentially of hammers that rotate at high speed (500 to 1500 rpm) and that are fastened to a metal plate, through which the cane is forced to pass via a narrow space ranging from 10 to 25 mm, so that the cane cells are “opened” and thereby prepared for the subsequent milling (extraction) stage.
The extraction stage consists of the milling of the cane by means of sets of rollers (three-roller combinations). Each milling unit usually consists of four three-roller milling combinations, by which the cane is pressed (crushed) under high pressure in order to extract the sugars. A typical extraction unit contains from four (4) to seven (7) three-roller milling combinations.
The milling rollers are driven by electric motors, steam turbines, or hydraulic systems. The milling stage typically consumes between 40 and 60% of the total energy required for the production process, thereby characterizing the operation as one with a high energy demand.
The first milling stage results in the production of a stream of liquid (the primary juice) that has a high saccharose content, which is sent for the manufacture of sugar or for the production of first-generation ethanol.
After the second milling stage, the mixed juice is extracted. This mixed juice consists of the juice obtained from the second grinding stage plus the juices produced during the adjacent stages, as well as the water added during the milling stage. Despite having a lower saccharose content and a lower purity level in comparison with the primary juice, this juice can also be used in the production of first-generation ethanol, in addition to being mixed with the primary juice for the production of sugar.
There is currently a growing demand for ethanol on the domestic and foreign markets, thanks to its use as a fuel and as an anti-knock agent in automobile engines. Brazil is the technological leader in the production of so-called “flex-fuel” vehicles, which use ethanol either in pure form or mixed with gasoline. Estimates indicate a significant growth in domestic demand for ethanol, thanks to the total or partial replacement of gasoline in various automotive vehicles. This increase is generating pressure to expand the area in which sugar cane is grown for the production of ethanol, which in turn exacerbates the onset of conflicts associated with land occupancy and land use, as well as the environmental issues inherent in sugar-cane cultivation.
In addition to the use of ethanol as a fuel, its processing as a raw material is awakening increasing interest in the chemical industry. Rising petroleum prices, combined with the non-renewable nature of this resource, illustrate the true feasibility of developing technological platforms such as so-called “biorefineries” that use readily available and relatively inexpensive renewable resources. In this context, the production of ethanol and of other highly worthwhile and industrially applicable chemicals from renewable resources, such as sugar-cane bagasse, has emerged as a potentially attractive alternative technology. In particular, the production of ethanol from the cellulose present in bagasse (i.e., cellulosic ethanol) has awakened a growing interest, thanks to its numerous benefits economic, strategic, social, and environmental benefits.
The process of producing cellulosic ethanol from bagasse requires the conversion of the cellulose into glucose, and the subsequent use of microorganisms to convert the glucose into bioethanol. However, native cellulose is heavily protected by the lignin-carbohydrate matrix, such that the cellulose is very resistant to hydrolytic action, with the result that the processes for converting cellulose into glucose are slow. Due to the association of cellulose with the hemicelluloses and with lignin, the access of several chemical agents (e.g., acids and alkalis) and biochemical agents (e.g., enzymes and microorganisms) used in fermentation-based processes for the production of cellulosic ethanol is substantially restricted. The cellulose matrix is organized in the form of fibers that are joined by hydrogen bridges and Van der Waals bonds, forming a rigid molecular structure (microfibrils) with diameters ranging from 10 to 30 nm. Moreover, the high crystallinity of the cellulose makes it extremely difficult to convert the cellulose into fermentable sugars through the use of hydrolysis processes. The sugars in turn are converted into ethanol. Therefore, ethanol production processes require initial treatment of the biomass (i.e., pre-treatment) in order to “open” the cellulosic matrix to the action of the hydrolysis agents, including, in particular, the enzymes. The regions of low crystallinity (i.e., the amorphous regions) present in the microfibrils are susceptible to enzymatic action, such that pre-treatment of the biomass can be omitted.
Pre-treatment of a lignocellulosic biomass is one of the most significant operational stages in terms of direct cost, and also has a substantial effect on the costs of the preceding and subsequent stages of the process. Basically, pre-treatment relates to the operations for the preparation of the raw material (i.e., grinding and impregnation), as well as to the hydrolysis (acid or enzymatic) of the cellulose (i.e., the loading and consumption of enzymes or acids, and the reaction rates); the generation of products that inhibit enzymatic hydrolysis and alcoholic fermentation; the saccharide concentrations of the resulting hydrolysates; the purification of the intermediate products; the treatment of waste; mechanical agitation; and the generation of energy. Within this context, the proper integration of the various operations must be sought. The performance of a pre-treatment technique must be evaluated in terms of its effect on the costs associated with the preceding and subsequent stages, as well as its effect on the operating costs, the cost of the raw material, and the cost of capital. Accordingly, the pre-treatment per se must be highly efficient in terms of its yield, selectivity, functionality (i.e., ensuring that the cellulose is accessible to the hydrolytic agents), operational simplicity, industrial health and safety, and environmental considerations, while also reducing the consumption of chemical supplies, energy, and utilities. Generally speaking, an efficient pre-treatment of sugar-cane bagasse for the production of ethanol should produce a cellulosic pulp whose fibers are readily accessible and responsive to the acidic or enzymatic hydrolytic agents (i.e., a pulp whose fibers possess the property of digestibility) and also ensure adequate recovery of the pentoses, while simultaneously limiting the generation of compounds that inhibit the enzymes and the microorganisms that are used in the fermentation process. Eco-efficient pre-treatment systems are also characterized by factors associated with the use of inexpensive catalysts, the recycling of consumable materials, and the generation, from the lignin, of byproducts having a high added value.
Although several pre-treatment techniques are potentially applicable to sugar-cane bagasse, comparative studies based on the data available in the literature are particularly difficult, because of the differences in the research methodologies, in the physical characteristics of the material, and in the methods for the preparation of the raw material. However, attention must be paid to the importance of improving and expanding the level of knowledge about the various types of pre-treatment, as well as about the effect of each process on the other operations. Such a step can facilitate the selection of equipment and of the operational sequences of the system as a whole, and reduce the risks associated with the implementation of the process on an industrial scale. It can also reveal opportunities for improvement throughout the integrated system, thereby leading to the optimization of operational efficiency while minimizing the overall costs of ethanol production.
Various methods for the pre-treatment of lignocellulosic plant biomasses have been suggested over the course of the last two decades. They can be divided into physical methods, chemical methods, biological methods, and combinations thereof. The physical methods (e.g., pelletization and milling) convert the biomass into fine powder, increasing the specific surface area of the cellulose, such that its hydrolysis is relatively easy. The major disadvantage of this method is its high energy consumption. For bagasse, the milling of the cane can be viewed as an operation for the pre-treatment of the fiber. Irradiation of the cellulosic fiber with gamma rays breaks the β-1,4 glycosidic bonds of the cellulose. The result is an increase in the specific surface area and a reduction in the crystallinity of the cellulose, such that its hydrolysis rate tends to increase. However, this method is considered too expensive to be implemented on an industrial scale. The option consisting of pre-treating the biomass by pyrolysis requires the use of very high temperatures (greater than 300° C.), causing rapid decomposition of the cellulose, but with the production of gaseous compounds and the formation of tarry residues. Acid hydrolysis of the solid fraction under moderate conditions converts the cellulosic fragments into glucose. Despite its relative operational simplicity, the overall efficiency of pyrolysis of the lignocellulosic biomass is low, because of the high saccharadic losses and the reduced glucose selectivity, in addition to the formation of fermentation-inhibiting compounds. The physico-chemical pre-treatment processes that use diluted acid, high-pressure steam, or hot water allow the selective removal of the hemicelluloses, producing (pre-hydrolyzed) saccharidic solutions with a high pentose content and a reduced lignin content. Alkaline processes tend to encourage greater dissolution of the lignin and less solubilization or fragmentation of the hemicelluloses.
Although many treatment methods have been the subject of experiments in recent years, there is a growing need to develop alternative technologies that are efficient in terms of overall cost and economic competitiveness. Basically, selective extractions of non-cellulosic components (i.e., lignin and the hemicelluloses) have been achieved at relatively modest costs through the use of alkalis or acids. In particular, pre-treatments using water steam, dilute sulfuric acid, ammonia, and calcium hydroxide (i.e., lime) have emerged as some of the most promising options. Table 1 shows some of the operational conditions used in different pre-treatments of biomasses, such as sugar-cane bagasse and corn stover.
There are similarities between the major methods involving the acid pre-treatment of the biomass (e.g., hot water, steam explosion, and hydrolysis with dilute acid) for the production of ethanol, because all of the methods are based on the combined action of water and the hydronium cation (H+) in different proportions and at different severity levels in the process.
The pre-treatment known as “steam treatment” (often referred to as the “steam explosion” method), which originated in the Masonite process used in the manufacture of pressboard, is one of the most widely used methods for converting lignocellulosic plant biomasses. When a lignocellulosic material is heated to relatively high temperatures with saturated steam, followed by the sudden decompression of the equipment, a brown slurry resulting from the fragmentation of the biomass is produced. After the material is washed, the liquid is separated, and adhesives are added, the pressboard is produced. In Brazil, certain companies have used sugar-cane bagasse in the production of pressboard products for the furniture industry.
Pre-treatment with steam has chemical and physical effects during the conversion of the lignocellulose, with the chemical reactions predominating. The biomass is treated with saturated steam at a temperature of 160° C. to 240° C. (at pressure of approximately 6 to 34 bar) during a reaction time of 1 to 15 minutes. After this period, decompression is applied to the system, and the material is collected in an expansion tank (also known as a “flash tank” or “blow tank”). During the steam treatment of the biomass, the hemicelluloses are idolized, and certain bonds between the cellulose and lignin are broken. The structure of the biomass becomes more susceptible to penetration by the water, acids, and enzymes, such that the hydrolytic potential of the cellulose is increased. The carbohydrates released from the hemicelluloses may suffer thermal degradation, while the lignin may undergo partial fragmentation and be dragged to the hydrolysate. The breakdown products that are produced may have an inhibitory effect on the subsequent operations. Hydrolysis in steam treatments may be catalyzed by organic acids (e.g., acetic acid) formed by the splitting of the functional groups present in the hemicelluloses. In such cases, autohydrolysis of the hemicelluloses (which is a characteristic of autocatalytic processes) is observed. Catalyst acids (SO2 and H2SO4) and Lewis acids (FeCl3, ZnCl2) can be used, which lead to an increase in the recovery of hemicelluloses sugars, as well as facilitating, during the subsequent stages, the hydrolysis of the cellulose present in the pre-treated pulp. The pre-treatment of biomasses that contain a high level of highly acetylated hemicelluloses (as is the case with bagasse) requires minimal quantities of catalyst acids. Thus, the use of these catalyst acids has an effect similar to that of chemical pre-treatment with dilute acid, while requiring a much smaller amount of liquid. Moreover, steam pre-treatment is similar to the hydrothermolysis (“hot water”) process, but larger loads of solids can be used in steam pre-treatment. This method is particularly worthwhile, given that it offers advantages associated with greater concentration of the hydrolysates, lower water consumption, and the generation of fewer liquid effluents. Steam pre-treatment can be viewed as a process that employs a mature technology, such that, of the methods described here, it is the closest to commercial implementation.
Hydrothermolysis (the “hot water” method, also known as “solvolysis” or “aquasolv”), uses compressed water in contact with the biomass for 1 to 15 minutes at temperatures between 170° C. and 230° C. At these temperatures, the water promotes the cleavage of the hemiacetal bonds of the carbohydrates, releasing acids during the hydrolysis of the biomass. In this process there is no need to reduce the size of the biomass particles, which tend to break up upon contact with the water during the so-called “cooking” process. Approximately 40% to 60% of the biomass is dissolved during the process, with the cellulose removal ranging from 4% to 22%. More than 90% of the hemicelluloses are recovered when acid is used as a catalyst for the hydrolysis of the resulting liquid; however, reduced saccharide concentrations, on the order of 0.5 to 6.0 g/liter, are obtained. Flow-through reactors and batch reactors can be used, in countercurrent and co-current configurations. In flow-through reactors, the hot water passes through a stationary biomass bed, thereby encouraging the hydrolysis of the lignocellulosic components, which are carried out of the reactor. Large quantities (35% to 60%) of lignin are removed during this process. Generally, because of the solubilization of the lignin, the use of special separation systems is required for suitable recovery of the hemicelluloses. Cellulosic pulps with a high level of fiber reactivity are typically produced, and the hydrolysate produced during the hydrolysis of these pulps tends to display adequate fermentability in ethanol. The use of catalyst acids makes the hot-water method similar to pre-treatment with dilute acid.
However, the hot-water process has major disadvantages in comparison with the steam-explosion system. Smaller loads of solids (e.g., 1% to 8%) must be used, because of the formation of inhibitors in the hydrolysates that are produced when solids concentrations greater than 10% are used. The amount of water used in the hot-water process is usually much larger than the amount used in the steam-explosion process, thereby producing very dilute hydrolysates, which tends to cause operational problems during the subsequent stages of the overall system. It should be pointed out that when hydrolysates are used as an agent for the dilution of molasses in fermentation systems that use microorganisms that convert pentoses, this problem is smaller and less important.
The hydrolysis process with dilute acid has been used industrially in the production of furfural, serving as a potentially worthwhile technological option for the pre-treatment of lignocellulosic biomasses. Basically, the hemicelluloses are removed, thereby producing pulps with a high level of fiber reactivity. Although sulfuric acid is customarily used as the hydrolytic agent, other acids (e.g., nitric, hydrochloric, and phosphoric acid) may also be used.
Basically, the mixture (i.e., the solution consisting of the acid and the biomass) may be heated indirectly in the reactor or directly through the injection of steam, in which case it bears some resemblance to the steam-explosion system. The acid is added to the liquid and percolates through the stationary biomass bed, after being sprayed onto the mass or even mixed with the biomass by means of mechanical stirring. The use of sulfuric acid has some drawbacks, such as corrosion of the equipment and the need to neutralize the resulting liquid (i.e., the hydrolysate), in addition to the formation of fermentation inhibitors. It should be emphasized that, thanks to the relatively easy removal of the hemicelluloses from the bagasse, the processes that use dilute acid can be implemented under relatively moderate processing conditions (e.g., 160° C. to 170° C.), with reduced formation of these inhibitors, while pulps with reactive fibers are obtained. The hydrolysis processes that use dilute acid require a raw material with a low ash content and low levels of other impurities, because of the buffering effect of such substances, which leads to a high consumption of acid. Washing the biomass prior to the pre-treatment is necessary in order to prevent this problem.
Pre-treatment processes with dilute acid in flow-through reactors use H2SO4 at concentrations on the order of 0.05% to 0.07%, which are much lower than the concentrations used in batch systems (i.e., 0.7% to 3.0%). Moderate temperatures (140° C. to 170° C.) are used in the first stage, the hydrolyze the most reactive hemicellulose fraction, whereas in the second stage more severe conditions (180° C. to 200° C.) are used, in order to hydrolyze the more recalcitrant hemicelluloses. Approximately 30% to 50% of the lignin is extracted, whereas approximately 80% to 95% of the hemicelluloses (predominantly in the form of monomers) are recovered. The pre-treated pulp has a high level of fiber reactivity, with enzymatic digestibility on the order of 90%. However, the process requires complex equipment configurations, in addition to an elevated hydromodule and high levels of water and energy consumption.
In comparison with the acid systems, the alkaline pre-treatment processes typically use moderate operating conditions in terms of temperatures and pressures. The major effect of the pre-treatment consists of the removal of the lignin from the biomass, thereby promoting a higher level of reactivity of the fiber. The alkali (usually sodium hydroxide or lime) tends to cause swelling of the biomass, so that the crystallinity of the cellulose decreases, while the specific surface contact area and the porosity of the cellulose both increase. The lignin-carbohydrate bonds are broken, and the structure of the lignin is fragmented. In some cases, the pre-treatment can be performed at room temperature. However, relatively lengthy reaction times are required, on the order of hours or even days. Unlike the acid systems, one major limitation of the alkaline processes consists of the need to recover the alkalis, so as to ensure that the process is appropriately economical. Because the alkaline processes cause substantial delignification of the biomass, these system should preferably be used in the pre-treatment of materials that have a low lignin content (e.g., agro-industrial wastes), with a view toward minimizing the amount of lignin present in the hydrolysate. The alkaline pre-treatment techniques under consideration for the production of ethanol are currently being tested only at the laboratory level and in pilot units.
The pre-treatment of bagasse using calcium hydroxide (i.e., lime) has certain advantages in terms of the cost of the reagent, the safety of the process, and the possibility of recovering the alkali in the form of calcium carbonate, through a reaction with the carbon dioxide produced during the alcoholic fermentation stage. The carbonate can then be converted into the hydroxide, through the use of established conventional industrial techniques. The addition of oxygen or air (as in so-called “wet alkaline oxidation”) tends to result in lignin removal on the order of 80%. However, such processes produce hydrolysates with a high lignin content, such that the use of lignin-carbohydrate separation systems is required for recovery of the hemicelluloses.
The wet alkaline oxidation process consists of treating the biomass with water and oxygen at temperatures above 120° C. A variant of the method, known as “wet alkaline peroxide oxidation,” consists of using H2O2 as the oxidizer, with reaction times on the order of 2 to 8 hours at temperatures between 30° C. and 70° C. Sodium carbonate, calcium hydroxide (i.e., lime), or sodium hydroxide is generally used as the hydrolysis and delignification agent.
Oxidative alkaline pre-treatments produce pulps with a high level of fiber reactivity, due to the accessibility of the cellulosic matrix to the enzymes. However, a large amount of lignin is oxidized and solubilized during these processes, so that it cannot be used as a fuel, thereby compromising the energy efficiency of the overall system. Furthermore, certain fermentation inhibitors (e.g., organic and phenolic acids) are formed in the hydrolysates that are produced, thereby compromising the subsequent stages.
The AFEX (“Ammonia Fiber Explosion”) process is the alkaline version of the steam-explosion pre-treatment process. Basically, there is an increase in the reactivity of the cellulosic fraction, due to its swelling, combined with the hydrolysis of the hemicelluloses and the disintegration of the fiber. The biomass is subjected to the effect of liquid ammonia (at a ratio of 2 kg per kg of biomass) at a temperature of 160° C. to 180° C., at pressure of 9 to 17 bar, for a period of 10 to 20 minutes. Then the pressure in the system is rapidly released, and the “exploded” material is collected in the flash tank. The advantages of this method include the high level of reactivity of the fiber, the minimal generation of fermentation-inhibiting compounds, and the recovery of the ammonia. However, the AFEX method does not promote the high level of hemicellulose solubilization that occurs in the acid processes, allowing the hemicelluloses to be recovered in the resulting hydrolysates. The SHFEX (“Sodium Hydroxide Fiber Explosion”) process uses sodium hydroxide under similar conditions, but with advantages associated with the recovery of the alkali, in addition to greater safety of the process. However, both processes produce hydrolysates with a high lignin content, such that the use of lignin-carbohydrate separation systems and recovery of the alkali are necessary.
Pre-treatment systems that use CO2 as an hydrolysis agent (e.g., the “CO2 Explosion” and “Supercritical CO2” systems) can be viewed as potentially worthwhile long-term technological options for the pre-treatment of sugar-cane bagasse, using the CO2 produced during the alcoholic fermentation stage. Basically, the CO2 is converted into in situ carbonic acid, such that the hydrolysis of the hemicelluloses is substantially increased. In economic terms, this method is more efficient than the AFEX process, in addition to not producing the fermentation inhibitors that are generated during steam pre-treatment. However, pre-treatment with CO2 has been less efficient than the other methods, in terms of the production of pulps with a high level of fiber reactivity. The pre-treatment of bagasse impregnated with 0.05% H2SO4, using supercritical CO2, allows satisfactory recovery of the hemicelluloses, on the order of 82%; however, the pre-treated pulp tends to display enzymatic digestibility of only 50%.
Based on the foregoing description, various solutions have been proposed and protected with a view toward energy savings in the production of ethanol.
U.S. Pat. No. 4,326,063 [sic] describes an integrated process for the production of ethanol, in which the sugar cane is cut and triturated so as to produce a mass of fiber and juice, which is then digested enzymatically in order to convert the contents of the fibers into fermentable sugar. The digestion product is then separated into a fibrous residue and a liquid fraction containing the sugars.
The fibrous residue then undergoes a second enzymatic digestion process combined with fermentation, thereby generating a new fibrous residue and a new, partially fermented liquid fraction, which are then separated.
The liquid fractions are then combined and fermented for the production of ethanol, which is then recovered.
This dual digestion of the sugar cane is the key factor for the economic management of the process, by ensuring that a majority of the fermentable material is extracted from the sugar cane and that this bagasse is burned in order to generate energy during the process.
In U.S. Pat. No. 4,356,196, alfalfa and other plants are treated with ammonia at high pressures, to increase their digestibility and protein availability. The cellulose can also be broken down enzymatically to produce glucose, which is then converted into ethanol through conventional processes.
U.S. Pat. No. 5,037,663 describes a process for increasing the chemical and biological reactivity of cellulose and/or hemicellulose in animal feedstuffs. This process involves placing the material in a pressurized vessel and bringing it into contact with a volatile agent, such as ammonia, whose vapor pressure is greater than atmospheric pressure at ambient temperatures. Contact is maintained for a period sufficient to allow the agent to swell the cellulose of the material. The pressure is then rapidly reduced to atmospheric pressure, causing the boiling of the agent and the explosion of material.
Similar treatments are described in U.S. Pat. Nos. 6,416,621, and 7,189,306, and in U.S. documents No. 2008/0008783, No. 2007/0031953, No. 2007/0031918, and No. 2007/0031919.
The present invention differs from these documents in that it provides energy savings through the use of a stage consisting of the milling of the biomass, particularly sugar cane, using a smaller number of three-roller milling combinations, without fully exhausting the cane juice and with a stage consisting of subjecting the cane resulting from the said milling to a less severe chemical treatment.
With regard to another aspect, U.S. Pat. No. 5,266,120 describes a process for the chemical pre-treatment of sliced sugar beets, in which the sliced sugar beets are placed on a line and soaked with a cold solution of calcium monosaccharide in order to fix this compound on the said slices. The patent provides a circulation system in which the byproducts formed by the breakdown of the calcium compound and the subsequent reaction with the sugars from the sugar beets are avoided.
U.S. Pat. No. 5,772,775 describes how, in order to achieve an efficient juice-extraction process, compaction of the bed should be avoided, so as to prevent low rates of percolation and expulsion of the juice. Accordingly, ages-extraction process that includes stages consisting of air displacement and the displacement of the juice from the fibrous material by means of a so-called “plug-flow” (tubular reactor) process, with the removal and separation of the juice.
The present invention differs from these documents, in that it teaches an integrated process for the treatment of the biomass, which consists of a mechanical stage (i.e., defibration and milling of the biomass), in conjunction with a subsequent stage involving the physico-chemical treatment of the resulting lignocellulosic material.
As mentioned hereinabove, the processing of cane sugar in juice-preparation and juice-extraction systems constitutes an operational stage that involves a level of energy consumption that is significantly substantial within the context of the overall energy balance of the integrated production system (for both sugar and ethanol). In this setting, the use of ages-extraction system that contains a shorter series of stations (i.e., preparation areas and three-roller milling combinations) enables significant energy savings, thus characterizing an eco-efficient system. Furthermore, the simplification of the extraction process tends to produce fibrous fractions (i.e., bagasse) containing higher levels of saccharose.
The use of bagasse pre-treatment processes implemented under severe conditions (i.e., high temperatures and pressures) tends to increase considerably the breakdown of the saccharose and other carbohydrates present in the biomass, resulting in a loss of production and a lower ethanol yield. In this context, the development of an extraction system associated with a pre-treatment process conducted under moderate conditions (i.e., less severe conditions) enables a significant increase in the energy efficiency of the integrated system for the production of sugar and first-generation ethanol. Furthermore, the reduced energy demand results in a smaller amount of bagasse burned in the boiler for the production of steam and energy, thereby increasing the availability of this biomass for the production of cellulosic ethanol and other products of industrial value.
In short, based on all of the foregoing considerations, it can be said that the current state of the art does not anticipate or suggest the teachings of the present invention, which recommends the development of a simplified system for the preparation of sugar cane and the extraction of juice with less energy consumption (in comparison with the conventional system), in conjunction with a process for the pre-treatment of the lignocellulosic material (including, in particular, the bagasse), with a view toward the production of sugar (and other carbohydrates), first-generation ethanol, cellulosic ethanol (i.e., second-generation ethanol), as well as other products of potential industrial value.